Determination of e/m
- Determine e/m
- Confirm negative polarity of the electron
- Deflection of electrons in magnetic field—Lentz’s Law
- Determine magnetic field as function of the acceleration voltage at a constant fine beam diameter
The tube’s n electron beam system consists of an indirectly heated oxide cathode, a Wehnelt cylinder and a perforated anode, in neon residual gas at a precisely set pressure. Integrated measurement marks for parallax-free determination of the diameter of the fine beam is also part of the electron beam assembly. Ionization of the gas atoms along the path of the electron produces a sharply defined, visible fluorescent beam. The tube is mounted on a base.
| Specifications | |
| Gas | Neon |
| Gas pressure | 1.3X10E-5 |
| Filament voltage | 4-14V AC/DC |
| Filament current: | 300-450 mA |
| Wehnelt voltage: | 0 – 50V |
| Anode voltage: | 200-300 V |
| Anode voltage: | <0.3mA |
| Diameter of fine beam path: | 20 –120 mm |
| Division spacing: | 20 mm |
| Tube diameter: | 160 mm |
| Total height including base: | 260 mm |
| Base plate: | 115X115X35 mm |
| Weight: | 820 g |
| TEL 8481420 e/m tube with base | $985 |
Helmholtz Coils The Helmholtz coils are designed for use with the e/m tube. The coils can be switched to in parallel or in series. A spring clip on the top crossbar can be used to mount a Hall sensor for magnetic field measurements.
| Specifications | |
| Coil diameter: | 295 mm |
| Coil spacing: | 150 mm |
| Turns per coil: | 124 |
| DC resistance | 1.2 Ohms each |
| Maximum coil current: | 5 amps |
| Weight: | 4.1 Kg |
| TEL 8481500 Helmholtz coils | $545 |
Additionally required:
Power Supply TEL-33000
Connecting leads
Complete e/m system
TThe complete e/m system consists of the TEL 8481420 e/m Tube and Base, the TEL 8481500 Helmholtz coils, and the TEL U33000 power supply for the tube and Helmholtz coils.
| TEL 8481SYS Complete e/m System |
Valid through January 2009 |
Fine Beam tube, without base
Tube only for the e/m system.
| TEL U8481440 e/m tube only | $820 |
Flat Coil in a Rotatable FrameIn conjunction with the pair of Helmholtz coils (TEL-8481500), this device is intended for experiments involving the law of induction. The flat coil is mounted on a plexiglass frame with a rotary bearing. The electrical connection to the coil is established via sliding contacts. A hand crank and pulley on the rotary frame's axle are used to drive the coil.
| Specifications | |
| Number of turns: | 4000 |
| Effective area: | 41.7 cm2 |
| Dimensions: | 110x80x11 mm |
| Weight: | approx. 360 g |
| Maximum coil current: | 5 amps |
| Weight: | 4.1 Kg |
| TEL 8481510 Flat Coil in Rotatable Frame | $545 |